Hi all,
I have a 2000 dodge neon 174k, just did a big overhaul and shes running great. I just put a new magnaflow muffler on it and the rest of the piping is still in good shape from the factory. My friend and I were testing the converters with a heat laser gun and the primary tested great and was doing its job, the secondary one didnt seem to be filtering as well as the primary one. I have no engine lights on or anything, how do you know if your sencondary converter is still working or not? He tapped it with a rubber mallet to see if it was broken up inside but appeared to be solid. Just wondering if its something I should think of replacing, or just leave alone.

 

if it passes inspection, it works!

 

A 2nd-gen Neon only has one cat on it. Do you have pics of where of you were banging?

 

There is two, my friend who is a mechanic showed me. There is a primary Cat off the manifold with two O2 sensors on it. Then shortly after there is another Cat converter.

 

Ok. Well if you have some kind of custom DIY aftermarket setup, that may be. But the stock OEM setup on your car (and aftermarket kits) looks like this, from motor to the back of the car:

1. Manifold
2. Upstream O2 sensor
3. Catalytic Converter
4. Downstream O2 sensor
5. Possibly a resonator, depending on where your car came from, whether it had a '03 SRT4 exhaust bolted on to it, etc.

If you do in fact have a resonator beyond the last 02 sensor, then don't worry about it... there is nothing in there. Measuring the cat with a heat gun should show pretty hot results, since that is what it is supposed to do. The farther you go down the exhaust past the cat, the cooler the exhaust will become. Especially if you have a resonator... the piping in the resonator would be larger, meaning that the gas would have to expand to fill the extra empty space inside of it. This expansion and slow-down of the gases will cause them to cool even more.

So it sounds to me like what you are seeing with the infrared heat gun is perfectly normal for the conditions you mentioned. I wouldn't worry about it at all. Drive it and enjoy your new muffler.

 

There is no 2nd cat...these aren't Hondas